Add support for USB OTG

Change-Id: Id5ded1d14f01e4bd126115866e0bf3bd75d5cfcb
hammerhead: add charging led support

Also introduces led priority handling for
battery vs notification vs attention
(copied from jf-common).

Requires the hammerhead kernel led
always on support patch.

Change-Id: I1a2f3aae457c6d7e4e3c3f9ca39cbe42d39c3bc2
hammerhead: Always keep 3 buffers ready

 * Reduces overall jank system-wide

Change-Id: I37f6021237c81197063d3fd1fd7e5e07626490c9
hammerhead: Better mount options to improve performance

Change-Id: I18f7165c2ff8547b7968d946336d948fe30522b1
Remove bug report shortcut

Change-Id: I746bef196740e0443869c1a45ef110e19d57a13e
Inline kernel changes
Update build info